Diabetes is one of the major chronic diseases and it often leads to a substantial loss of quality of life. However, complications can be relieved by intensive insulin treatment, which, unfortunately, also increases the frequency severe hypoglycaemia (low blood glucose). In 1959 Somogyi described how insulin overtreatment, leading to hypoglycaemia, can cause prolonged hyperglycaemia (elevated blood glucose), but numerous studies, especially in the 80ies, have not been able to produce significant evidence for his theory. However, in a recent model-based study we have introduced a hypothesis suggesting that the phenomenon is clinically much more important than previously anticipated. The present pilot study assesses the feasibility of employing a computer model to data from a 32 hour intensive monitoring period from 3 patients to infer the reaction to spontaneous hypoglycaemia, thereby contributing to the verification of the hypothesis and to an understanding of the phenomenon. Regarded separately, the number of patients in the present study is far too small to justify any conclusion, but, taken together with our previous studies, there seems to be substantial evidence for the existence of the hypoglycaemic counter-regulation. Furthermore, the present study seems to suggest that cortisol release, triggered by the hypoglycaemic attack, may play an important role in provoking the hypoglycaemic counter-regulation, and that further studies are clearly required to verify this hypothesis